From left to right the saints Eustathius Placidus, Samonas and Gurias.

Wikipedia gives for the left one (for the other two, see later picture):
"According to legend, prior to his conversion to Christianity Eustace was a Roman general named Placidus, who served the emperor Trajan. While hunting a stag in Tivoli near Rome, Placidus saw a vision of a crucifix lodged between the stag's antlers. He was immediately converted, had himself and his family baptized, and changed his name to Eustace (Greek: Ευστάθιος (Eustáthios), "well stable", or Ευστάχιος (Eustáchios), "fruitful/rich grain"). A series of calamities followed to test his faith: his wealth was stolen; his servants died of a plague; when the family took a sea-voyage, the ship's captain kidnapped Eustace's wife Theopista; and as Eustace crossed a river with his two sons Agapius and Theopistus, the children were taken away by a wolf and a lion. Like Job, Eustace lamented but did not lose his faith. He was then quickly restored to his former prestige and reunited with his family. There is a tradition that when he demonstrated his new faith by refusing to make a pagan sacrifice, the emperor Hadrian condemned Eustace, his wife, and his sons to be roasted to death inside a bronze statue of a bull or an ox, in the year AD 118. However, the Catholic Church rejects this story as "completely false"

For their lifes see next pictures.